The general feeling about USC is the Trojans recruit so well that when star players leave, equally talented players step in to take their places.

This is the year to prove it.

When the Trojans start spring practice, a top priority will be restocking a defense that lost nine starters. But even the process of rebuilding the nation's stingiest defense won't overshadow an impending quarterback competition.

Here's a look at the Trojans as they begin spring practice.

USC AT-A-GLANCE

C.J. Gable returns to lead a talented stable of running backs for USC.

The Trojans averaged almost 200 rushing yards per game in '08, and the running game should be exceptional again. The entire line returns intact, led by Kristofer O'Dowd and Jeff Byers - who was granted a sixth season by the NCAA. Running behind that line will be C.J. Gable, Stafon Johnson and Joe McKnight, who all rushed for more than 600 yards a year ago. Free safety is in good hands with Taylor Mays, a two-time All-America selection.

Help is needed

All three starting linebackers from '08 are gone and are expected to be selected in the NFL draft; two likely will go in the first round. No doubt, the Trojans have capable players stepping in, but can they perform to the level of their predecessors? Rebuilding also has to be done along the defensive line, which loses three starters, and in the secondary. And then there's the matter of replacing quarterback Mark Sanchez.

Keep an eye on

LB Chris Galippo: Galippo, a sophomore, was considered the nation's top high school inside linebacker in 2007. He had 12 tackles last season as the backup to All-American Rey Maualuga, but he'll have many more opportunities in '09.

DE Everson Griffen: Griffen, a junior, earned freshman All-America recognition in '07, then lost his starting job in '08. He'll move back into the starting lineup. Whether he can stay there will be determined.

WR Ronald Johnson: He emerged as a deep threat last season as a sophomore and now needs to become an all-around threat since Patrick Turner has completed his eligibility.

His time is now

McKnight came to USC billed as an explosive breakaway threat. He has been that – just not often enough. In two seasons, he has scored just five touchdowns. He even lost his role as the punt returner. Injury problems have been an issue, and he needs to stay on the field and prove he can be a consistent threat. If not, the Trojans already have two proven backs. Junior wide receiver David Ausberry also needs to distinguish himself. He was a coveted four-star prospect in 2006, but he had just six catches last season as a reserve. Ausberry will be vying for a starting role this spring.

The buzz

Perhaps no position battle in the nation will draw as much attention as the competition to replace Sanchez. Junior Mitch Mustain and sophomore Aaron Corp, both highly touted recruits, will battle for the job. Mustain has more experience and started eight games at Arkansas in 2006, but Corp is more mobile. If neither establishes himself, true freshman Matt Barkley, rated the nation's top pro-style passing prospect, could become a factor in the competition. Barkley already is enrolled and will participate in spring practices.

Olin Buchanan is the senior college football writer for Rivals.com. He can be reached at olin@rivals.com.